Vehicle brake-operating system



Sept. 16, 1930. G. SMITH VEHICLE BRAKE OPERATING SYSTEI Original FiledMarch 27, 1928 Patented Sept. 16, 1930 UNITED STATES PATENT ()FFICEGEQRGE L. SMITH, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO UNITEDSTATES ORDNANCE COMPANY, OF WASENGTON, DISTRICT OF COLUMBIA, A COR-PORATION 0F VIRGINIA VEHICLE BRAKE-OPERATING SYSTEM Original applicationfiled March 27, i928, Serial No. 265,040. Divided and this applicationfiled October 8,

1929. Serial No. 398,182.

My invention relates to a multiple brake operating system for motorvehicles shown in my prior application 265,040, of which latter thisapplication is a division.

Generally speaking it is the purpose of my. invention to provide a brakesystem of the type specified which will eliminate a large number of theparts of such systems as now constructed with resultant economy inproduction and installation; and which will give great braking powerwith safety under all operating conditions which may be encountered.

The conventional design of motor vehicles permits the useof a brake onthe propeller shaft for braking the vehicle through the rear. wheels,but the use of such a brake has been heretofore avoided owingito theadditional stresses imposed thereby on the drive mechanism between theengine and rear wheels. "My invention contemplates the use of a brake onthe propeller shaft of an automobile; but in association with novelfeatures ofconstruction and arrangement which serve to reduce theaforementioned stresses to a point well below those produced by theengine. so that such a brake. can be used with safety and thus enable meto attain a material reduction in the production cost of motor vehiclesequipped with brake systems of the general type specified, by theelimination from such systems of rear Wheel brakes and their operatingconnections.

.In carrying my invention into practice I combine front wheel brakeswith a propeller shaft or transmission brake, and by a peculiar andnovel method of control produce a brake systenicapable ofproducingpowerful brakingunder those conditions where powerfulbraking action isneeded and safe braking under those conditions where excessive bra-kingaction cannot be used, such as on slippery pavement.

' Itis well known that the weight supported by the front and rear axlesof a motor vehicle varies with the severity of the retarding forceimposed by'brake application during vehicle travel.- As a result of theimposition of such retarding force during vehicle'travel weight isremoved from the rear axle of the such.

vehicle and transferred to the front axle. The amount of weighttransferred from the rear axle to the front axle under the conditionsspecified is proportional to the retarding force and is readilycomputable.

As the weight carried by the axles of a motor vehicle controls thepressure of the wheel tires on the road and as this pressure controlsthe amount of braking force which the tires can deliver to the road, itis evident that, if proper, ellicient and safe braking is to be attainedduring vehicle travel, means must be provided for varying the front andrear brake forces of the brake system. In other words as the weight iseased off the rca r axle and wheels and shifted to the front axle andwheels by the retarding force incident to brake application duringvehicle travel, the brake force should be eased off the rear of thebrake system and built up in the front thereof, to thereby prevent therear wheels locking long prior to the front wheels being subjected to abrake force suflicient to effect their locking, with needless sacrificeof brakepowcr resulting.

My invention therefore, also contemplates the provision in a brakesystem of the type specified, of means for varying the relative power ofthe front and rear brakes while the brakes are in operation and bycombining means with front wheel brakes and a transmission brake Iproduce the equivalent of a four wheel brake system wherein theretarding forces delivered to the road surface by each of the severalwheel tires is approximately proportional to the tire pressure on suchsurface, so that danger of locking a wheel by braking is reduced whileat the same time brake power is increased. Furthermore, the increasedbrake power derived from the front brakes produces a greater transfer ofweight from the rear axle to the front axle of the vehicle so that therear wheels are more easily locked and therefore a transmission brake ofrelatively small iower can be utilized. Thus the maximum brake stresseson the drive mechanism are reduced well below those produced by theengine and danger of failure or excessive wear of such mechanism isavoided.

:1 pressed'and thus restore'proper service 1 ing until such time as heto adjust the t entire brake system; This restoration of properservicebraking, under not be used, such as it is evident that undersuchconditions and r To further explain why my device as previously statedgives safe braking under conditions where excessive braking action canonslippery pavement,

upon brake application theretardation of the vehicle would be slight andthe transfer of weight to the front axle-and wheels correspondinglysmall, so that the brakepower of the rear wheels would be about;asgreat" as that of the frontwheels thus-utilizing to the best advantageall four points of Contact of the wheels Wltll the slipperysurfacei Thisaction is especially desirable in descending a slippery hillat aconstant'speed as much better control ofthe vehicle would be' ob-.

tained; v.

, To furtherreduce possible dangc'rof-los-f ing brake power in myimproved system and to comply. with legal requirements specifying twoseparate sets of brakes .I employ a hand lever cooperatlvely associatedwith the transmission brake and operable not only to -i brake thevehicle 111 case ofemergency,

but also operable to tighten the transmission brake so that, should thedriver find the permissible movement of the brake foot pedal ineffectiveto' properly service the vehicle by pulling up the hand lever todirectly tighten the transmission brake and to cause the front brakes insubsequent opei'a- 7 tion to tighten-up as the brake pedal is debrak-'has the opportunity the conditions specified, constitutes one of thesafety elements of my; improved brake system. I I

In the drawings chosen to llustrate my 111-- vention, the scope whereofis set forth in the appended-claims-e. I

constructedin accordance with my invent-ion and Fig. 2, arear view'thereof. I c V i w Referring to the drawing, lQdenotes the footbrakepedal ofa motor vehicle mounted on a'pivot 11. Toftheishort arml2'of'the pedal lt) is pivoted an equalizer bar, 13 havinga downwardlydirectedektension'13 t free end of WlllClI'CitlTlQS an inertiaweight Atransmission brake 15 is mounted on the propeller shaft 16 andis-composedofiabr alie 7 band l i-brake lever 18, tensionboltl9 adjusting nut 20, ands anchor 21; An operat- .ing shaft" 22 for thistransmissionbrake-is mountedfon "an associated vehicle by means" ofendbearin'gs 2 3and 24k and attached there-- to: is a lever 25 whichisconnected to the brake lever-18 by a link 26 so thaticloekwise rota 7' 7tion of shaft 22 (F g. 1) will pull on link 26 and apply thetransmissionbrake The I the brakes, he could overcome this conditionwhile driving Fig.'1"s a side elevation of'a brake. system.

- adjustment by pulling by means ofgthe bearings associated vehicle 33'at its ends from which the-brakepullrods 34 extend forward tothe frontwheel brakes A. A lever 35 is1keyed to this shaftB O about in line withlever 28 and connection between lever 35 and yoke 131s made by the pullrod 36, so that depression ofpe'dallO-willlikewise set the front wheel.brakes.

The mechanism heretofore ates as follows :f'Depression oftthe pedal 10for front and'rear wheels proportional to the Weight carried by thesewheels when car' is at rest. NVhen the car is slowed downfby the brakesduring-vehicle travel the r'etarda tion causes the weight 42 onextension 13 to "swing forward,'increasing thepull on rod 36 1 anddecreasing the pull onrod' 29'; This increases in turn theforceoflth'efront brakes and decreases that of the transmission brake inproportion as the transfenof car weight from rear axle and wheels tofront axleand wheelstak'es place. 7 l i Z r c My invention'further'embodiesa n emei V 27 pivoted in the usual v gency brake" leverdescribed oper 29,50 that de i An' operating shaft 30 for frontwheel 31and 32. This 7 shaft v carries downwardlyeX-tendmg levers pulls on bothrods 29an'd 36, thefpull of each rod being. such' as-to'generatebrakeforces manner. art 43 and connected at its lower end to force one end oftheb'andi 17 tov'vardsthe nut 20 is screwed fwith a link 44. The rear'end fof thi's'link connects with" the cam lever 45. l This' cam lever4:5 is c pivotally' carried by thefbr'ake adjusting nut and has acamsurfacee "lever'18 thejsame as would' beftli'e case when up, said nutbeing ad-c ustable by disconnecting link or from lever 45 and utilizin'glever 45 in lieu of a wrench v to rotate said nut To assuref'safebrakingshould anyfpar'ts from link 2'6" up to pedal, '1

10 be broken I provide a back step 47' for lever 18 to"react'against sothat the brake 17 can be setby' hand, lever 27; I This construction notonly i 7 connections to the brake 17,.but also permits the driver to getthe equivalentof a brake gives two independent V 1 1a r t Ibackcthehand-lever anotch ortwo'onthef 'ratchet-Zar'c 48. As 7 a thiscanjbejdone wliile car is inmotionit'isf thereforepossibletoYtightenoradjust the, brakes whil e'driving and avoid.dangerof accident due toins'uflieient'brakeactionr c I :Thebrake stopit? provided to, permitloositive setting of the transmission brake by vhand lever in cases of emergencyto neutral the handlever 27 also permitsthe use of this" 1 'ize the action ofthe inertia weight 42 as lowsglffbothpedal 10 and hand lever 27 it are operated at the same time the;efi'ec't of each would be to; setfallabrakes infl the .1 proportioncontrolled "by the weight 452' until hand lever were pulled back farenough to force lever 18 against the stop 47. After erable to apply thebrake while said band adjusting means is maintained in a fixed thispoint is reached further pull on hand position of adjustment.

lever would increase power of transmission brake independently of thatof front brakes and the action of inertia. weight would be cut out ofthe system.

To summarize the action of my system I provide first an automatic meansof varying the front and rear brake forces so that when the vehicle isslowed down by brake action the wei 'ht 42 operates the parts to buildup the Iront brake force and decrease the rear brake force. Also if forany reason the driver desires more brake power from the rear system hecan manually increase the rear brake force by pulling up on hand lever27 as above described. Should his brakes be badly worn down he can setlever 27 back a notch or two which will tighten up on the transmissionbrake. This will cause weight 42 to swing forward slightly when lever 10is depressed and thus tighten up front brakes also. Should the entirehookup back to brake lever 18 be placed out of operation the brake 17could still be set by the hand lever 27.

I claim:

1. An external contracting rake band, a tension bolt and a nutadjustable thereon for contracting said band, a service brake leverconnected to one end of said tension bolt and to one end of the band,and an emergency lever connected to said nut and to the other end ofsaid band whereby either lever is operable to contract the band whilesaid nut remains in a fixed position of adjustment on said bolt.

2. In a brake, a brake band, a tension bolt, a lever pivoted to one endof said bolt and to one end of the band, a member adjustable along saidbolt, a lever pivoted to said member and operatively connected to theother end of the band, and a pair of brake applying devices connectedrespectively to said levers.

3. In a brake, a brake band, a bolt connected to one end of the band, amember adjustable along said bolt and cooperating with the other end ofthe band by such adjustment to adjust the band, a device cooperatingwith said bolt and member and with one end of the band to apply thebrake while said member is in a fixed position of adjustment along saidbolt, and a device co operating with said bolt and member and with theother end of the band to apply the brakes while said member is in afixed posi tion of adjustment along the bolt.

4. In a brake, a brake band, band adjusting means connecting the ends ofthe band, a lever connected with said means and to one end of the band,and another lever connected with said means and the other end of theband whereby either lever is op- In testimony whereof I hereuntosignature.

GEORGE L. SMITH.

affix my

